1970 Chevy Camaro 5 Inexpensive Modifications - Budget Bliss
5 inexpensive ways to go fast for less
From the April, 2006 issue of Chevy High Performance
By Scott Crouse
Over the next few pages, we'll be honoring the budget-minded high-performance enthusiast inside each of us who believes in stretching the dollar to the nth degree. He's with you at the speed shops, junkyards, and swap meets with one common goal--going fast! For some, he represents the high-end racer who has to decide between supercharging and turbocharging his application, while others with a similar craving are limited to choosing between 87- and 91-octane. Either way, budgets affect us all in one form or another.
Meet Martin Weinreb, owner of a beautiful backyard '70 Camaro. Purchased over a decade ago, it's been sitting in the backyard awaiting some tender loving care. Like most of us, his budget was small but his dreams certainly weren't. After years of planning and searching for deals, he eventually found away to turn his dreams into a reality.
The paint and body were kept car-cover pristine, while the Muncie four-speed and 350ci small-block awaited an overhaul. After scouring swap meets, junkyards, and speed shops, Martin managed to procure a five-speed manual transmission out of a third-gen Camaro and gave the 350ci a quick once-over. The motor features swap-meet parts, including a pair of World Products SR (stock replacement) cylinder heads, a hydraulic flat-tappet, single-pattern Lunati camshaft (0.507 inch of valve lift and 235 degrees of duration at 0.050 inch, with a LSA of 108 degrees), a single-plane intake mani-fold, and a 750-cfm Holley carburetor. Everything about the engine's configuration was absolutely budget-limited, even down to the aged 1 5/8-inch Hedman Hedders. These were originally designed to fit a Chevelle, yet custom-hammered to fit the Camaro's home-built 2 1/2-inch exhaust system. With engineering like this, you better believe Martin's swap-meet specials went the distance.
We knew there was a thing our two to be learned from this backyard mechanic. Here's an average guy whose love for power is so immense he wouldn't let his passion be snuffed out by high-priced racers with top-end parts. It was then we realized that Martin was the perfect candidate to strap his '70 Camaro onto the rollers to see what kind of power gains can be had with a minimal cash outlay. With that in mind, we made arrangements to utilize Westech Performance's chassis dyno and contacted SA Engine Design to get their recommendation on achieving our goals. Their input was rather simple: Start with the ignition, move onto the fuel, then increase the airflow. Check it out--you'll be amazed at the type of gains to be had for around $500.
Peak Power: 334 lb-ft and 268 hp
Average Power: 285 lb-ft and 209 hp
As soon as we arrived at the Westech Dyno facility, the Camaro was strapped to the dyno and readied for a baseline pull. Total timing was set to 36 degrees of total advance, the engine coolant temperature sat around 185 degrees, and the oil was warmed to 200 degrees. We could tell the engine was running rough but decided to make a pull anyway to see exactly what we were starting with. As luck would have it, the engine ran all the way through its powerband but showed signs of stumbling, netting only 286 lb-ft of torque at 3,200 rpm and 227 hp at 5,200 rpm, while averaging 243 lb-ft/182 hp between 1,900 rpm and 5,800 rpm. After a quick look around, we noticed the No. 4 spark-plug wire had fallen against its header tube completely, disabling one of the cylinders. This not only robbed us of easy engine power, but created an overly rich air/fuel oxygen-sensor condition as well.
When we initially pulled the burnt wire, we noticed it was a suppression core design. These wires are generally inexpensive and mainly built for low-performance factory engines that don't require a lot of spark energy. Since our engine already had an induction upgrade, we wanted to make sure our electrical system was up to snuff. We added a set of high-performance Flame Thrower 8mm spiral-core Pertronix spark-plug wires. To be sure there wouldn't be any more hot header mishaps, we used a set of Made For You wire separators before firing the Camaro back to life. After running the engine through its powerband we saw substantial peak gains of 48 lb-ft and 41 hp, with average gains of 42 lb-ft and 27 hp. The rear-wheel gains were impressive, which makes it important for us to mention the majority of the gained power came from being able to ignite all eight cylinders instead of seven. The upgraded ignition components may not have been directly related to the huge power increases, but their ability to deliver a consistently hotter spark at high rpm makes them a necessity on any high-performance engine.
With more performance testing on the way, we wanted to make sure the cylinders would receive the greatest amount of spark energy a stock engine application could have. This called for a Pertronix Flame Thrower HEI upgrade kit that would offer 6.9 amps and 50,000 volts while measuring only 1/2 ohm of resistance. The Pertronix HEI upgrade is not only legal in all 50 states, but it can be used on any HEI Chevy, Pontiac, Olds, or Buick, if distributor parts-swapping is ever an issue.
Peak Power: 334 lb-ft and 271 hp
Average Power: 289 lb-ft and 215 hp
Once our cylinders were firing smoothly, we moved onto the engine's fuel curve. Up until this point, the air/fuel (A/F) ratios were close but could be improved. A single-plane intake manifold draws less vacuum than a dual-plane design, causing it to pull less fuel from the carburetor's main metering circuit (jets). This condition creates a slightly lean A/F ratio at high-rpm operation. To correct for this, we attempted to increase our stock jetting from 67-primary and 73-secondary by two jet sizes, to 69-primary and 75-secondary. The added fuel made a slight difference, posting the same 334 lb-ft at 3,200 rpm and a slight gain at 271 hp at 5,100 rpm. With averages of 41 lb-ft of torque and 6 hp, the jetting definitely made a positive change. While a larger jet may have made slightly greater power, it would more than likely hurt the fuel curve when our new and improved Weiand dual-plane manifold went into place.
Peak Power: 351 lb-ft and 281 hp
Average Power: 291 lb-ft and 223 hp
Fuel and spark support the combustible power of oxygen molecules. That said, we wanted to add more air to our engine's cylinders, and it just so happens that Holley's Weiand product line offers improved intake manifolds for both street and strip applications. We opted for a medium-rise dual-plane manifold and couldn't wait to see how much more efficiently it would run. Weiand manifolds come with most of what is needed to make it work, but installation is up to the user. This requires some simple tools, silicone, and a pair of intake-manifold gaskets. With a set of Fel-Pro intake-manifold gaskets on hand, we performed the swap in about a half hour. As soon as our silicone dried, the small-block was back in action, delivering even more power. This time around we saw 351 lb-ft at 3,500 rpm and 281 hp at 5,000 rpm. The average numbers jumped up as well, posting 291 lb-ft and 223 hp. Obviously, a dual-plane Weiand design was the way to go for our hot street application.
The Pertronix HEI upgrade...
The Pertronix HEI upgrade kit comes with everything required to deliver a hotter spark and adjust the timing curve.
A new coil and high-performance...
A new coil and high-performance module will make sure the HEI puts out 6.9 amps and 50,000 volts to each plug wire.
By adding more fuel to our...
By adding more fuel to our single-plane combination, the peak power numbers climbed slightly; however, the average numbers improved by 41 lb-ft and 6 hp.
Using Holley's non-stick gaskets...
Using Holley's non-stick gaskets would have saved these guys a lot of time.
ProForm offers the cool-looking,...
ProForm offers the cool-looking, inexpensive valve cover in the foreground, while Fel-Pro's intake gaskets made sure our intake manifold sealed properly.
It looks good and makes power...
It looks good and makes power too. What more could a gearhead ask for? The Weiand manifold comes in a polished or as-cast finish.
While not recom-mended by...
While not recom-mended by coolant manufacturers, we reused the antifreeze from the radiator. Every penny counts, and Mr. Budget was hard at work.
Notice the minute notches...
Notice the minute notches cut into the four-holes of the Torque Swirl spacer. These direct air and fuel in a spinning motion to help swirl the mixture and make more power.
Open-plenum spacers add more...
Open-plenum spacers add more volume to the intake manifold. Ours worked best in the upper rpm ranges and would really shine on a high winder above 5,000 rpm.
These ProForm pieces made...
These ProForm pieces made power and looked good doing it. Their light-weight body and roller-tip construction was worth 9 peak horsepower over the stock units.
Peak Power: 357 lb-ft and 285 hp (4-hole)
Average Power: 301 lb-ft and 227 hp
Sometimes, no matter how much fuel- tuning comes into play, the perfect tune will more often than not elude you without the right combination of parts. One way to fine-tune an engine's air/fuel mixture is by trying different carburetor-to-intake manifold spacers. This time, we wanted to see what kind of gains could be had with a four-hole spacer, as opposed to an open-plenum design. Since Trans-Dapt Performance Products offers spacers in all shapes and sizes, we tested their 1-inch-tall Torque Swirl four-hole design against a 1-inch-tall open-plenum design. The spacers come with all the necessary installation hardware and can be bolted on in minutes. Our first test would run the four-hole setup and, hopefully, improve the engine's average power numbers. After warming the engine and stabilizing the test conditions, we ran the engine for more power. The Torque Swirl design amazed us, posting 357 lb-ft at 3,300 rpm and 285 hp at 5,200 rpm. The averages also took our breath away, breaking 301 lb-ft and 227 hp. With such great results already on the table, it was hard to imagine that the open-plenum design could do any better. We swapped the spacers and made our next pull, with slightly less torque at 349 lb-ft at 3,700 rpm and 289 hp at 5,900 rpm. The open design moved the rpm powerband up nearly 400 rpm, showing that more potential power could be gained on a higher-revving engine. While the four-hole Torque Swirl spacer may have been more ideal for our application, the open-plenum design did post higher peak horsepower numbers. Each spacer did amazingly well on the dyno, showing its strengths per application. What we could not show here was how effective the spacers are at diminishing heat transfer from the manifold to the carburetor. By touch, we can say that the manifold would burn our hands, while the carburetor base plate felt as cool as the room temperature. Since our mild small-block was set up for 5,500 rpm and under action, the four-hole Torque Swirl spacer went back onto the engine for the next test.
Peak Power: 357 lb-ft and 294 hp (4-hole)
Average Power: 298 lb-ft and 231 hp
The final test of the day consisted of swapping our stock 1.5:1-ratio rockers out for a set of roller-tipped, aluminum-body 1.5:1-ratio ProForm roller rockers. The camshaft inside the engine was initially chosen by SA Engine Design and turned out to be ideal for the application. This allowed us to test the benefits of the rockers without any complication, as their lightweight roller-tip construction would be put to the test. Once our engine's parameters were steadied, we spun the rollers to reap even more power than before with 357 lb-ft at 3,700 rpm and 294 hp at 5,900 rpm peak figures. Again we were pleased with our parts' performance, as the averages came in at 298 lb-ft and 231 hp, posting the highest net average of the day.
Our engine was now making 71 lb-ft and 67 hp over our baseline numbers, and Mr. Weinreb couldn't wait to get his Camaro back on the street. Saving money and avoiding hassles is the name of the game when you're trying to gain the best bang for the buck. And this time around, CHP (with the help of your real-world enthusiast) managed to show us all how to get the job done!
Behind the Scenes
A potent small-block can consume quite a bit of fuel during an upper-rpm pull. Our engine did not require very much fuel to make 294 rear-wheel horsepower at 6,000 rpm, but future upgrades will demand additional fuel as engine power increases. In order to make sure our fuel system would be capable of feeding a high-performance small-block, we installed a 130-gph mechanical fuel pump, an adjustable fuel pressure regulator, and a steel braided line kit from Holley. For complete install details, contact Earl's Performance Plumbing.
|Parts Guide: |
|Manufacturer||Description||Part Number||Price: |
|Pertronix||8mm Universal wires||808290||$49.95 |
|GM||HEI upgrade kit||D8000||$119.95 |
|Holley/Weiand||Unpolished manifold||8120||$115.69 |
|Holley/Weiand||Jet kit||36-181||$41.95 |
|Trans-Dapt||1-inch four-hole spacer||2531||$34.88 |
|ProForm||1.5:1 roller rocker||66907||$147.95 |
|Total $510.37 |